RUT850 Firmware
Summary
You can upgrade your router's Firmware via the System->Firmware window. There two possible options for Firmware upgrade: From server and From File. From file means that you yourself have to upload a valid Firmware file to the router; From server downloads the newest Firmware from the FOTA server. If there are no newer versions than your current one, you will see a "No new firmware" sign on the top right corner of the screen. When you upgrade your Firmware, make sure to check the Keep all settings field, otherwise all of your current configurations will be lost and the router reset to its default state. If, for some reason, you decide to downgrade your router's Firmware version, your router will be reset either way.
STM8 Firmware is a Firmware for the router's LEDs and Sleep Mode.